The invention refers to a plant-based construction material. The invention further refers to said plant-based construction material and objects that are produced from this construction material.
Many construction materials produced from renewable primary products have been developed and applied in order to satisfy the need for an ecological construction method in accordance with nature. Various combinations on the basis of vegetable raw materials are known in the art.
Straw and clay are historical ecological construction materials that have been used very frequently. However, their application is restricted by the limited stability and durability of this material combination. Thus, timber framing infills made of straw and clay do not meet today's modern requirements with respect to thermal and acoustic insulation.
Furthermore, various attempts have been made to use wood as a vegetable raw material in combination with cement as a sustainable construction material. However, the low strength resp. surface strength and the excessive density and therefore relatively high weight of the resulting components are often problematic. Also, the noise and heat insulating properties are relatively poor due to the high proportion of cement required as a binder.
In the search for a construction material having a maximum content of renewable primary material and good chemical, physical and mechanical properties, tests have also been made with miscantus (China reed). Due to its high silicon content, inter alia, this plant genus offers ideal properties for processing into a stable and durable construction material.
However, the production of a viable construction material on the basis of a vegetable aggregate is only possible if the latter is bonded in the binder matrix. This condition is fulfilled by a mineralization of the vegetable raw materials. Therefore, a qualitative utilization of renewable vegetable raw materials for modern, contemporary constructions is subject to the quality and efficiency of this mineralization in particular.
Furthermore, as is generally known, constructions require the use of different structural components and elements having specific properties according to the intended application. Thus, besides the components for the construction e.g. of walls, there are other elements such as prefabricated plasterboards.
Accordingly, the problem is to produce a universally applicable plant-based construction material, i.e. a construction material that is suitable for virtually all conceivable applications due to a basic composition that is adaptable in view of the intended application and thus of the required properties and, as the case may be, supplementable by specific, also application-oriented additives.
According to the disclosure of EP-1,108,696 A1, a premineralization of renewable fibrous raw material particles such as wood, hemp, and/or reed particles is achieved by means of cement, preferably Portland cement as a mineralizer. Here, the premineralization of the vegetable raw materials is accomplished in a separate process step, after which the raw materials treated with the mineralization liquid are dried. The pretreated plant parts may then be used for producing concrete or mortars. The drawback of this approach is that an additional treatment of the vegetable raw materials for the purpose of premineralization is necessary. An additional process step is also associated to additional costs, and the construction industry is forced to save additional process steps due to the constant cost pressure. Increased costs for ecological construction methods strongly reduce the attractiveness of such methods and cannot bring about to the application of such alternative plant-based construction materials instead of conventional construction materials.
Therefore, according to WO-A-02/12145, a premineralization of the vegetable aggregate is omitted in order to make the production of concrete and mortars cheaper and simpler on the basis of this aggregate and still to obtain favorable properties with respect to thermal insulation, acoustic insulation, bending and compression strength. However, particularly with regard to the selected mineralizer, this might not be accomplished optimally. Furthermore, an adaptation of the construction material in view of different required properties is not being mentioned, so that the fields of application are expected to be relatively limited.
It is an object of the present invention to solve the problem set forth above and to overcome the disadvantages of the prior art.